Diagram of a horizontal pH scale ranging from 0, on the far left, to 14, on the far right. The left side, starting with 0, is the most acidic and shows a small image of a car battery. The scale becomes less acidic as it gradually moves toward the center, where it is labeled neutral. Then, the scale becomes more basic as it nears the right side to the number 14. The number 14 shows a picture of drain cleaner.